i found that it was much easier to swap diff's if the beam was dropped from the car

much more access to the bolts you need to get to and more room to swing the hammer

the long bolt running the width of the diff is the most difficult to remove, plenty of penetrating fluids should get it moving after a couple of thwacks with a hammer

also, the drive shaft bolts can be easier accessed by removing the cv boot from the driveshaft, once they are cracked they are only finger tight but if you do find that you round the heads on the torx bolts the replacements came in T45 heads rather than the original earlier T40's which were more prone to rounding